all clients have to have an internal database. some clients, like nostrudel, have all but a full relay inside them. if it's a full PWA, the database and app can be run without an internet connection, it's all cached in the browser. including the database.

Hey @Séimí Mac Síomón , the new version of YakiHonne mobile app has an offline mode, you can browse content, interact with them and even compose notes that all gets published automatically when you’re back online.